<?php

/**
 * Marker constant for Services_JSON::decode(), used to flag stack state
 */
define('SERVICES_JSON_SLICE',   1);

/**
 * Marker constant for Services_JSON::decode(), used to flag stack state
*/
define('SERVICES_JSON_IN_STR',  2);

/**
 * Marker constant for Services_JSON::decode(), used to flag stack state
*/
define('SERVICES_JSON_IN_ARR',  3);

/**
 * Marker constant for Services_JSON::decode(), used to flag stack state
*/
define('SERVICES_JSON_IN_OBJ',  4);

/**
 * Marker constant for Services_JSON::decode(), used to flag stack state
*/
define('SERVICES_JSON_IN_CMT', 5);

/**
 * Behavior switch for Services_JSON::decode()
*/
define('SERVICES_JSON_LOOSE_TYPE', 16);

/**
 * Behavior switch for Services_JSON::decode()
*/
define('SERVICES_JSON_SUPPRESS_ERRORS', 32);
class Services_JSON
{
	
	function Services_JSON($use = 0)
	{
		$this->use = $use;
	}
	
	/**
	 * convert a string from one UTF-16 char to one UTF-8 char
	 *
	 * Normally should be handled by mb_convert_encoding, but
	 * provides a slower PHP-only method for installations
	 * that lack the multibye string extension.
	 *
	 * @param    string  $utf16  UTF-16 character
	 * @return   string  UTF-8 character
	 * @access   private
	 */
	function utf162utf8($utf16)
	{
		// oh please oh please oh please oh please oh please
		if(function_exists('mb_convert_encoding')) {
			return mb_convert_encoding($utf16, 'UTF-8', 'UTF-16');
		}
	
		$bytes = (ord($utf16{0}) << 8) | ord($utf16{1});
	
		switch(true) {
			case ((0x7F & $bytes) == $bytes):
				// this case should never be reached, because we are in ASCII range
				// see: http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8
				return chr(0x7F & $bytes);
	
			case (0x07FF & $bytes) == $bytes:
				// return a 2-byte UTF-8 character
				// see: http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8
				return chr(0xC0 | (($bytes >> 6) & 0x1F))
				. chr(0x80 | ($bytes & 0x3F));
	
			case (0xFFFF & $bytes) == $bytes:
				// return a 3-byte UTF-8 character
				// see: http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8
				return chr(0xE0 | (($bytes >> 12) & 0x0F))
				. chr(0x80 | (($bytes >> 6) & 0x3F))
				. chr(0x80 | ($bytes & 0x3F));
		}
	
		// ignoring UTF-32 for now, sorry
		return '';
	}
	
	/**
	 * convert a string from one UTF-8 char to one UTF-16 char
	 *
	 * Normally should be handled by mb_convert_encoding, but
	 * provides a slower PHP-only method for installations
	 * that lack the multibye string extension.
	 *
	 * @param    string  $utf8   UTF-8 character
	 * @return   string  UTF-16 character
	 * @access   private
	 */
	function utf82utf16($utf8)
	{
		// oh please oh please oh please oh please oh please
		if(function_exists('mb_convert_encoding')) {
			return mb_convert_encoding($utf8, 'UTF-16', 'UTF-8');
		}
	
		switch(strlen($utf8)) {
			case 1:
				// this case should never be reached, because we are in ASCII range
				// see: http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8
				return $utf8;
	
			case 2:
				// return a UTF-16 character from a 2-byte UTF-8 char
				// see: http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8
				return chr(0x07 & (ord($utf8{0}) >> 2))
				. chr((0xC0 & (ord($utf8{0}) << 6))
				| (0x3F & ord($utf8{1})));
	
			case 3:
				// return a UTF-16 character from a 3-byte UTF-8 char
				// see: http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8
				return chr((0xF0 & (ord($utf8{0}) << 4))
				| (0x0F & (ord($utf8{1}) >> 2)))
				. chr((0xC0 & (ord($utf8{1}) << 6))
				| (0x7F & ord($utf8{2})));
		}
	
		// ignoring UTF-32 for now, sorry
		return '';
	}
	
	/**
	 * encodes an arbitrary variable into JSON format
	 *
	 * @param    mixed   $var    any number, boolean, string, array, or object to be encoded.
	 *                           see argument 1 to Services_JSON() above for array-parsing behavior.
	 *                           if var is a strng, note that encode() always expects it
	 *                           to be in ASCII or UTF-8 format!
	 *
	 * @return   mixed   JSON string representation of input var or an error if a problem occurs
	 * @access   public
	 */
	function encode($var)
	{
		switch (gettype($var)) {
			case 'boolean':
				return $var ? 'true' : 'false';
	
			case 'NULL':
				return 'null';
	
			case 'integer':
				return (int) $var;
	
			case 'double':
			case 'float':
				return (float) $var;
	
			case 'string':
				// STRINGS ARE EXPECTED TO BE IN ASCII OR UTF-8 FORMAT
				$ascii = '';
				$strlen_var = strlen($var);
	
				/*
				 * Iterate over every character in the string,
				* escaping with a slash or encoding to UTF-8 where necessary
				*/
				for ($c = 0; $c < $strlen_var; ++$c) {
	
					$ord_var_c = ord($var{$c});
	
					switch (true) {
						case $ord_var_c == 0x08:
							$ascii .= '\b';
							break;
						case $ord_var_c == 0x09:
							$ascii .= '\t';
							break;
						case $ord_var_c == 0x0A:
							$ascii .= '\n';
							break;
						case $ord_var_c == 0x0C:
							$ascii .= '\f';
							break;
						case $ord_var_c == 0x0D:
							$ascii .= '\r';
							break;
	
						case $ord_var_c == 0x22:
						case $ord_var_c == 0x2F:
						case $ord_var_c == 0x5C:
							// double quote, slash, slosh
							$ascii .= '\\'.$var{$c};
							break;
	
						case (($ord_var_c >= 0x20) && ($ord_var_c <= 0x7F)):
							// characters U-00000000 - U-0000007F (same as ASCII)
							$ascii .= $var{$c};
							break;
	
						case (($ord_var_c & 0xE0) == 0xC0):
							// characters U-00000080 - U-000007FF, mask 110XXXXX
							// see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8
							$char = pack('C*', $ord_var_c, ord($var{$c + 1}));
							$c += 1;
							$utf16 = $this->utf82utf16($char);
							$ascii .= sprintf('\u%04s', bin2hex($utf16));
							break;
	
						case (($ord_var_c & 0xF0) == 0xE0):
							// characters U-00000800 - U-0000FFFF, mask 1110XXXX
							// see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8
							$char = pack('C*', $ord_var_c,
							ord($var{$c + 1}),
							ord($var{$c + 2}));
							$c += 2;
							$utf16 = $this->utf82utf16($char);
							$ascii .= sprintf('\u%04s', bin2hex($utf16));
							break;
	
						case (($ord_var_c & 0xF8) == 0xF0):
							// characters U-00010000 - U-001FFFFF, mask 11110XXX
							// see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8
							$char = pack('C*', $ord_var_c,
							ord($var{$c + 1}),
							ord($var{$c + 2}),
							ord($var{$c + 3}));
							$c += 3;
							$utf16 = $this->utf82utf16($char);
							$ascii .= sprintf('\u%04s', bin2hex($utf16));
							break;
	
						case (($ord_var_c & 0xFC) == 0xF8):
							// characters U-00200000 - U-03FFFFFF, mask 111110XX
							// see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8
							$char = pack('C*', $ord_var_c,
							ord($var{$c + 1}),
							ord($var{$c + 2}),
							ord($var{$c + 3}),
							ord($var{$c + 4}));
							$c += 4;
							$utf16 = $this->utf82utf16($char);
							$ascii .= sprintf('\u%04s', bin2hex($utf16));
							break;
	
						case (($ord_var_c & 0xFE) == 0xFC):
							// characters U-04000000 - U-7FFFFFFF, mask 1111110X
							// see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8
							$char = pack('C*', $ord_var_c,
							ord($var{$c + 1}),
							ord($var{$c + 2}),
							ord($var{$c + 3}),
							ord($var{$c + 4}),
							ord($var{$c + 5}));
							$c += 5;
							$utf16 = $this->utf82utf16($char);
							$ascii .= sprintf('\u%04s', bin2hex($utf16));
							break;
					}
				}
	
				return '"'.$ascii.'"';
	
			case 'array':
				/*
				 * As per JSON spec if any array key is not an integer
				 * we must treat the the whole array as an object. We
				 * also try to catch a sparsely populated associative
				 * array with numeric keys here because some JS engines
				 * will create an array with empty indexes up to
				 * max_index which can cause memory issues and because
				 * the keys, which may be relevant, will be remapped
				 * otherwise.
				 *
				 * As per the ECMA and JSON specification an object may
				 * have any string as a property. Unfortunately due to
				 * a hole in the ECMA specification if the key is a
				 * ECMA reserved word or starts with a digit the
				 * parameter is only accessible using ECMAScript's
				 * bracket notation.
				 */
	
				// treat as a JSON object
				if (is_array($var) && count($var) && (array_keys($var) !== range(0, sizeof($var) - 1))) {
					$properties = array_map(array($this, 'name_value'),
							array_keys($var),
							array_values($var));
	
					foreach($properties as $property) {
						if(Services_JSON::isError($property)) {
							return $property;
						}
					}
	
					return '{' . join(',', $properties) . '}';
				}
	
				// treat it like a regular array
				$elements = array_map(array($this, 'encode'), $var);
	
				foreach($elements as $element) {
					if(Services_JSON::isError($element)) {
						return $element;
					}
				}
	
				return '[' . join(',', $elements) . ']';
	
			case 'object':
				$vars = get_object_vars($var);
	
				$properties = array_map(array($this, 'name_value'),
						array_keys($vars),
						array_values($vars));
	
				foreach($properties as $property) {
					if(Services_JSON::isError($property)) {
						return $property;
					}
				}
	
				return '{' . join(',', $properties) . '}';
	
			default:
				return ($this->use & SERVICES_JSON_SUPPRESS_ERRORS)
				? 'null'
						: new Services_JSON_Error(gettype($var)." can not be encoded as JSON string");
		}
	}
	/**
	 * array-walking function for use in generating JSON-formatted name-value pairs
	 *
	 * @param    string  $name   name of key to use
	 * @param    mixed   $value  reference to an array element to be encoded
	 *
	 * @return   string  JSON-formatted name-value pair, like '"name":value'
	 * @access   private
	 */
	function name_value($name, $value)
	{
		$encoded_value = $this->encode($value);
	
		if(Services_JSON::isError($encoded_value)) {
			return $encoded_value;
		}
	
		return $this->encode(strval($name)) . ':' . $encoded_value;
	}
	
	/**
	 * reduce a string by removing leading and trailing comments and whitespace
	 *
	 * @param    $str    string      string value to strip of comments and whitespace
	 *
	 * @return   string  string value stripped of comments and whitespace
	 * @access   private
	 */
	function reduce_string($str)
	{
		$str = preg_replace(array(
	
				// eliminate single line comments in '// ...' form
				'#^\s*//(.+)$#m',
	
				// eliminate multi-line comments in '/* ... */' form, at start of string
				'#^\s*/\*(.+)\*/#Us',
	
				// eliminate multi-line comments in '/* ... */' form, at end of string
				'#/\*(.+)\*/\s*$#Us'
	
		), '', $str);
	
		// eliminate extraneous space
		return trim($str);
	}
	/**
	 * decodes a JSON string into appropriate variable
	 *
	 * @param    string  $str    JSON-formatted string
	 *
	 * @return   mixed   number, boolean, string, array, or object
	 *                   corresponding to given JSON input string.
	 *                   See argument 1 to Services_JSON() above for object-output behavior.
	 *                   Note that decode() always returns strings
	 *                   in ASCII or UTF-8 format!
	 * @access   public
	 */
	function decode($str)
	{
		$str = $this->reduce_string($str);
	
		switch (strtolower($str)) {
			case 'true':
				return true;
	
			case 'false':
				return false;
	
			case 'null':
				return null;
	
			default:
				$m = array();
	
				if (is_numeric($str)) {
					// Lookie-loo, it's a number
	
					// This would work on its own, but I'm trying to be
					// good about returning integers where appropriate:
					// return (float)$str;
	
					// Return float or int, as appropriate
					return ((float)$str == (integer)$str)
					? (integer)$str
					: (float)$str;
	
				} elseif (preg_match('/^("|\').*(\1)$/s', $str, $m) && $m[1] == $m[2]) {
					// STRINGS RETURNED IN UTF-8 FORMAT
					$delim = substr($str, 0, 1);
					$chrs = substr($str, 1, -1);
					$utf8 = '';
					$strlen_chrs = strlen($chrs);
	
					for ($c = 0; $c < $strlen_chrs; ++$c) {
	
						$substr_chrs_c_2 = substr($chrs, $c, 2);
						$ord_chrs_c = ord($chrs{$c});
	
						switch (true) {
							case $substr_chrs_c_2 == '\b':
								$utf8 .= chr(0x08);
								++$c;
								break;
							case $substr_chrs_c_2 == '\t':
								$utf8 .= chr(0x09);
								++$c;
								break;
							case $substr_chrs_c_2 == '\n':
								$utf8 .= chr(0x0A);
								++$c;
								break;
							case $substr_chrs_c_2 == '\f':
								$utf8 .= chr(0x0C);
								++$c;
								break;
							case $substr_chrs_c_2 == '\r':
								$utf8 .= chr(0x0D);
								++$c;
								break;
	
							case $substr_chrs_c_2 == '\\"':
							case $substr_chrs_c_2 == '\\\'':
							case $substr_chrs_c_2 == '\\\\':
							case $substr_chrs_c_2 == '\\/':
								if (($delim == '"' && $substr_chrs_c_2 != '\\\'') ||
								($delim == "'" && $substr_chrs_c_2 != '\\"')) {
									$utf8 .= $chrs{++$c};
								}
								break;
	
							case preg_match('/\\\u[0-9A-F]{4}/i', substr($chrs, $c, 6)):
								// single, escaped unicode character
								$utf16 = chr(hexdec(substr($chrs, ($c + 2), 2)))
								. chr(hexdec(substr($chrs, ($c + 4), 2)));
								$utf8 .= $this->utf162utf8($utf16);
								$c += 5;
								break;
	
							case ($ord_chrs_c >= 0x20) && ($ord_chrs_c <= 0x7F):
								$utf8 .= $chrs{$c};
								break;
	
							case ($ord_chrs_c & 0xE0) == 0xC0:
								// characters U-00000080 - U-000007FF, mask 110XXXXX
								//see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8
								$utf8 .= substr($chrs, $c, 2);
								++$c;
								break;
	
							case ($ord_chrs_c & 0xF0) == 0xE0:
								// characters U-00000800 - U-0000FFFF, mask 1110XXXX
								// see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8
								$utf8 .= substr($chrs, $c, 3);
								$c += 2;
								break;
	
							case ($ord_chrs_c & 0xF8) == 0xF0:
								// characters U-00010000 - U-001FFFFF, mask 11110XXX
								// see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8
								$utf8 .= substr($chrs, $c, 4);
								$c += 3;
								break;
	
							case ($ord_chrs_c & 0xFC) == 0xF8:
								// characters U-00200000 - U-03FFFFFF, mask 111110XX
								// see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8
								$utf8 .= substr($chrs, $c, 5);
								$c += 4;
								break;
	
							case ($ord_chrs_c & 0xFE) == 0xFC:
								// characters U-04000000 - U-7FFFFFFF, mask 1111110X
								// see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8
								$utf8 .= substr($chrs, $c, 6);
								$c += 5;
								break;
	
						}
	
					}
	
					return $utf8;
	
				} elseif (preg_match('/^\[.*\]$/s', $str) || preg_match('/^\{.*\}$/s', $str)) {
					// array, or object notation
	
					if ($str{0} == '[') {
						$stk = array(SERVICES_JSON_IN_ARR);
						$arr = array();
					} else {
						if ($this->use & SERVICES_JSON_LOOSE_TYPE) {
							$stk = array(SERVICES_JSON_IN_OBJ);
							$obj = array();
						} else {
							$stk = array(SERVICES_JSON_IN_OBJ);
							$obj = new stdClass();
						}
					}
	
					array_push($stk, array('what'  => SERVICES_JSON_SLICE,
					'where' => 0,
					'delim' => false));
	
					$chrs = substr($str, 1, -1);
					$chrs = $this->reduce_string($chrs);
	
					if ($chrs == '') {
						if (reset($stk) == SERVICES_JSON_IN_ARR) {
							return $arr;
	
						} else {
							return $obj;
	
						}
					}
	
					//print("\nparsing {$chrs}\n");
	
					$strlen_chrs = strlen($chrs);
	
					for ($c = 0; $c <= $strlen_chrs; ++$c) {
	
						$top = end($stk);
						$substr_chrs_c_2 = substr($chrs, $c, 2);
	
						if (($c == $strlen_chrs) || (($chrs{$c} == ',') && ($top['what'] == SERVICES_JSON_SLICE))) {
							// found a comma that is not inside a string, array, etc.,
							// OR we've reached the end of the character list
							$slice = substr($chrs, $top['where'], ($c - $top['where']));
							array_push($stk, array('what' => SERVICES_JSON_SLICE, 'where' => ($c + 1), 'delim' => false));
							//print("Found split at {$c}: ".substr($chrs, $top['where'], (1 + $c - $top['where']))."\n");
	
							if (reset($stk) == SERVICES_JSON_IN_ARR) {
								// we are in an array, so just push an element onto the stack
								array_push($arr, $this->decode($slice));
	
							} elseif (reset($stk) == SERVICES_JSON_IN_OBJ) {
								// we are in an object, so figure
								// out the property name and set an
								// element in an associative array,
								// for now
								$parts = array();
	
								if (preg_match('/^\s*(["\'].*[^\\\]["\'])\s*:\s*(\S.*),?$/Uis', $slice, $parts)) {
									// "name":value pair
									$key = $this->decode($parts[1]);
									$val = $this->decode($parts[2]);
	
									if ($this->use & SERVICES_JSON_LOOSE_TYPE) {
										$obj[$key] = $val;
									} else {
										$obj->$key = $val;
									}
								} elseif (preg_match('/^\s*(\w+)\s*:\s*(\S.*),?$/Uis', $slice, $parts)) {
									// name:value pair, where name is unquoted
									$key = $parts[1];
									$val = $this->decode($parts[2]);
	
									if ($this->use & SERVICES_JSON_LOOSE_TYPE) {
										$obj[$key] = $val;
									} else {
										$obj->$key = $val;
									}
								}
	
							}
	
						} elseif ((($chrs{$c} == '"') || ($chrs{$c} == "'")) && ($top['what'] != SERVICES_JSON_IN_STR)) {
							// found a quote, and we are not inside a string
							array_push($stk, array('what' => SERVICES_JSON_IN_STR, 'where' => $c, 'delim' => $chrs{$c}));
							//print("Found start of string at {$c}\n");
	
						} elseif (($chrs{$c} == $top['delim']) &&
						($top['what'] == SERVICES_JSON_IN_STR) &&
						((strlen(substr($chrs, 0, $c)) - strlen(rtrim(substr($chrs, 0, $c), '\\'))) % 2 != 1)) {
							// found a quote, we're in a string, and it's not escaped
							// we know that it's not escaped becase there is _not_ an
							// odd number of backslashes at the end of the string so far
							array_pop($stk);
							//print("Found end of string at {$c}: ".substr($chrs, $top['where'], (1 + 1 + $c - $top['where']))."\n");
	
						} elseif (($chrs{$c} == '[') &&
						in_array($top['what'], array(SERVICES_JSON_SLICE, SERVICES_JSON_IN_ARR, SERVICES_JSON_IN_OBJ))) {
							// found a left-bracket, and we are in an array, object, or slice
							array_push($stk, array('what' => SERVICES_JSON_IN_ARR, 'where' => $c, 'delim' => false));
							//print("Found start of array at {$c}\n");
	
						} elseif (($chrs{$c} == ']') && ($top['what'] == SERVICES_JSON_IN_ARR)) {
							// found a right-bracket, and we're in an array
							array_pop($stk);
							//print("Found end of array at {$c}: ".substr($chrs, $top['where'], (1 + $c - $top['where']))."\n");
	
						} elseif (($chrs{$c} == '{') &&
						in_array($top['what'], array(SERVICES_JSON_SLICE, SERVICES_JSON_IN_ARR, SERVICES_JSON_IN_OBJ))) {
							// found a left-brace, and we are in an array, object, or slice
							array_push($stk, array('what' => SERVICES_JSON_IN_OBJ, 'where' => $c, 'delim' => false));
							//print("Found start of object at {$c}\n");
	
						} elseif (($chrs{$c} == '}') && ($top['what'] == SERVICES_JSON_IN_OBJ)) {
							// found a right-brace, and we're in an object
							array_pop($stk);
							//print("Found end of object at {$c}: ".substr($chrs, $top['where'], (1 + $c - $top['where']))."\n");
	
						} elseif (($substr_chrs_c_2 == '/*') &&
								in_array($top['what'], array(SERVICES_JSON_SLICE, SERVICES_JSON_IN_ARR, SERVICES_JSON_IN_OBJ))) {
							// found a comment start, and we are in an array, object, or slice
							array_push($stk, array('what' => SERVICES_JSON_IN_CMT, 'where' => $c, 'delim' => false));
							$c++;
							//print("Found start of comment at {$c}\n");
	
						} elseif (($substr_chrs_c_2 == '*/') && ($top['what'] == SERVICES_JSON_IN_CMT)) {
							// found a comment end, and we're in one now
							array_pop($stk);
							$c++;
	
							for ($i = $top['where']; $i <= $c; ++$i)
								$chrs = substr_replace($chrs, ' ', $i, 1);
	
							//print("Found end of comment at {$c}: ".substr($chrs, $top['where'], (1 + $c - $top['where']))."\n");
	
						}
	
					}
	
					if (reset($stk) == SERVICES_JSON_IN_ARR) {
						return $arr;
	
					} elseif (reset($stk) == SERVICES_JSON_IN_OBJ) {
						return $obj;
	
					}
	
				}
		}
	}
	/**
	 * @todo Ultimately, this should just call PEAR::isError()
	 */
	function isError($data, $code = null)
	{
		if (is_object($data) && (get_class($data) == 'services_json_error' ||
				is_subclass_of($data, 'services_json_error'))) {
			return true;
		}
	
		return false;
	}
	
}

